1. Field of the Invention
This invention relates generally to a processor-based computer system and, more particularly, to a computer system with dynamically configurable capacity (i.e., capacity-on-demand).
2. Description of the Related Art
The last several years have witnessed an increased demand for network computing, partly due to the emergence of the Internet. Some of the notable trends in the industry include a boom in the growth of Applications Service Providers (ASPs) that provide applications to businesses over networks and enterprises that use the Internet to distribute product data to customers, take orders, and enhance communications with employees.
Businesses typically rely on network computing to maintain a competitive advantage over other businesses. As such, developers, when designing processor-based systems for use in network-centric environments, may take several factors into consideration to meet the expectation of the customers, factors such as the functionality, reliability, scalability, and performance of such systems.
One example of a processor-based system used in a network-centric environment is a mid-frame server system. Typically, mid-frame servers are employed in high bandwidth systems requiring high availability factors. Minimizing system downtime is an important system management goal, as downtime generally equates to significant lost revenue. Typically, such computer systems are provided with replaceable components or modules that may be removed and/or installed without shutting down the system. This on-line replacement capability is commonly referred to as hot-pluggable or hot-swappable environment.
Unlike current desktop computer systems, in which the internal cards and devices are essentially disposable (i.e., they are replaced if they fail, and the defective part is discarded without repair), the individual components used to construct higher end systems, such as the mid-frame server described above, are typically returned to the manufacturer or a third-party vendor associated with the manufacturer for repair. Repaired units are then reinstalled in the same or in a different mid-frame server. These units are commonly referred to as field replaceable units (FRUs). In the service life of a particular FRU, it may be installed in multiple servers owned by different customers. Exemplary units that may be field replaceable, are system control boards, processing boards, memory modules installed on one of the processing boards, input/output (I/O) boards, power supplies, cooling fans, and the like.
Mid-frame servers are employed in high availability, high utilization applications. When a system is installed the processing demands on the server are estimated and the appropriate processing resources are provided. These resources include the number of processing boards, the number of processors on each board, and the like. The different processing boards may be subdivided into separate logical domains, so not only do the resource requirements for the entire server need to be determined, but also the resource requirements for each of the logical domains needs to be determined. In determining the processing requirements, there is a trade-off between meeting the average load and meeting the peak load. It is generally not economical for a server owner to purchase the level of over-capacity required to meet all peak load scenarios. Hence, there may be times when the server becomes overloaded during peak load periods. This may result in a slow-down in the system and/or delays in customer servicing.